JP3023815B2 - 4-cycle engine intake system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for a four-stroke engine, and more particularly to a cylinder block having a substantially horizontal cylinder, a cylinder head connected to the cylinder block, and a combustion chamber formed in the cylinder head. The present invention relates to an intake device for a four-stroke engine including:

[0002]

2. Description of the Related Art In recent years, a four-cycle engine having two cylinder axes arranged in a V-shape and having an electronically controlled fuel injection system has been proposed (for example, Japanese Utility Model Laid-Open No. 2-127779). reference). In this engine, a substantially Y-shaped distribution-type intake pipe is arranged inside a V-bank, and one injector is arranged upstream of a branch point to supply fuel.

[0003]

However, in the above-mentioned conventional engine, no special consideration is given to downsizing the intake device on the upstream side of the injector, so that the size of the engine is increased by the intake device. There is.

The present invention has been made in view of the above circumstances, and has as its object to reduce the size of the intake system of a four-stroke engine.

[0005]

To achieve the above object, an intake system for a four-stroke engine according to the present invention comprises a cylinder block having a substantially horizontal cylinder, a cylinder head connected to the cylinder block, and a cylinder block. In a four-stroke engine having a combustion chamber formed in a cylinder head, an intake passage extending substantially horizontally from the combustion chamber and opening to an outer wall of the cylinder head is formed in the cylinder head, and the cylinder head communicates with the intake passage. A first feature is that a surge tank to be operated is arranged on a side of the cylinder head, and a throttle body communicating with the surge tank is arranged below the surge tank.

Further, the present invention provides, in addition to the first feature described above,
A second aspect is that the four-stroke engine is a V-type multi-cylinder four-stroke engine having a pair of banks, and wherein the surge tank is disposed in an area between the pair of banks.
The feature of.

Further, the present invention provides, in addition to the first feature described above,
A third feature is that the four-cycle engine includes a plurality of cylinders arranged substantially in a vertical direction, and the surge tank is arranged along a line of the plurality of cylinders.

[0008] The present invention provides, in addition to the first feature described above,
A fourth feature is that an intake silencer connected to the throttle body is disposed at a side of the throttle body and at a position that does not interfere with the cylinder head.

Further, the present invention provides, in addition to the fourth feature described above,
The four-stroke engine is a V-type multi-cylinder four-stroke engine having a pair of banks, wherein the surge tank is arranged in a region sandwiched between the pair of banks,
A fifth feature is that the intake silencer is arranged outside the region.

[0010] The present invention, in addition to the fourth feature described above,
A sixth feature is that the four-stroke engine includes a fuel tank that supplies fuel to the injector, and the fuel tank is arranged on a side of the intake silencer.

Further, the present invention provides, in addition to the sixth feature described above,
The four-cycle engine has a pair of left and right banks.
A multi-cylinder four-stroke engine, wherein the surge tank is arranged in an area sandwiched between the pair of left and right banks, and the intake silencer and the fuel tank are juxtaposed right and left outside the area. The feature of.

Further, the present invention provides, in addition to the first feature described above,
An eighth feature is that the four-stroke engine is housed in an engine room defined by an engine cover above an extension case of an outboard motor, with its cylinder generally facing backward.

Further, the present invention provides, in addition to the eighth feature described above,
A ninth feature is that the engine room protrudes rearward from the rear end of the extension case, and at least a part of the throttle body is housed in the rear protruding portion.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 7 show an embodiment of the present invention. FIG. 1 is an overall side view of an outboard motor, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. FIG. 4 is a sectional view taken along line 3-3 of FIG.
5 is a sectional view taken along line 5-5 of FIG. 4, FIG. 6 is a sectional view taken along line 6-6 of FIG. 4, and FIG. 7 is an enlarged view of a main part of FIG.

As shown in FIGS. 1 to 4, the outboard motor O has a mounting member 3 connected to the extension case 1 via a plurality of bolts 2 at an upper portion thereof. V-type four-cylinder 4 via a plurality of bolts 4 on the upper surface
The cycle engine E is supported. An undercase 5 whose upper surface is open is connected to the mounting member 3 by a plurality of bolts 6. An engine cover 7 is detachably mounted on the upper part of the undercase 5. The engine cover 7 is coupled to the upper edge of the under case 5 via a seal member 8 provided on the lower edge thereof, and a pair of front and rear clips 9, 1
Fixed by 0. Thus, in the engine room 11 defined inside the engine cover 7, the crankshaft 12 is set to the vertical posture, and the pair of banks 1
The engine E is housed with the 3 _L and 13 _R expanded rearward.

A drive shaft 14 connected in series to a lower end of a crankshaft 12 of the engine E extends downward inside the extension case 1, and a lower end thereof is connected to a gear case 15.
Is connected to a propeller shaft 18 having a propeller 17 at the rear end via a bevel gear mechanism 16 provided inside the. A lower end of a shift member 19 is connected to a front portion of the bevel gear mechanism 16 so as to switch the rotation direction of the propeller shaft 18.

The upper mount 20 provided on the mounting member 3
And lower mount 21 provided on extension case 1
A swivel shaft 22 is fixed between the swivel shaft 22 and a swivel case 23 that rotatably supports the swivel shaft 22.
Is a stern bracket 24 attached to the rear end of the hull S.
Is supported via a tilt shaft 25 so as to be able to swing up and down.

The engine E has a V-shaped cylinder block 26 in plan view, a crankcase 27 which cooperates with the cylinder block 26 to define a crank chamber, and a pair of deck surfaces of the cylinder block 26. A pair of cylinder heads 28, 28
And head covers 29, 29 coupled to the heads 8, 28, respectively. The left and right head covers 29, 29 are the engine cover 7
Therefore, the interior of the engine room 11 is divided into a front space 30 located in front of the engine E and a rear space 31 located behind the engine E.
The front space 30 in addition to the control unit 33 of the controller 32 and the ignition plug such as electronically controlled fuel injection system, meshes with a gear 91 ₁ formed on the outer periphery of the flywheel 91 provided on the upper end of the crankshaft 12 A starter motor 93 having a pinion 92, an oil filter 94, and engine accessories such as an oil pump 95 provided at the lower end of the crankshaft 12 are housed. In the rear space 31, a fuel supply system and an intake system are housed. .

Referring to FIG. 5 and FIG.
Thus, each bank 13 of the engine E _L, 13_RIs horizontal
Provided with upper and lower two cylinders 34 each having an axis.
And four slidably fitted to each cylinder 34.
Pistons 35 are connected via connecting rods 36
It is connected to the crankshaft 12. Each cylinder 34 ...
Four combustion chambers 37... Formed corresponding to the top of
The fork formed on the cylinder heads 28, 28 respectively
Two intake valves 39, 39 connected to the intake port 38;
Exhaust ports 40a formed in the Linda heads 28, 28
And an exhaust port 40 formed in the cylinder block 26
b, one exhaust valve 41 and one spark plug 42
Are provided.

Each intake port 38 has an engine room 1
1, air is sucked through an intake silencer 43, an elbow 60, a throttle body 44, and a surge tank 45 disposed in the rear space 31.
The fuel injected from the injector 46 provided at 8 is mixed. On the other hand, the left and right banks 13 _L, 13 each two exhaust ports 40a of the _R, 40b ... a pair of exhaust passages 47, 47 formed in the vertical direction in the cylinder block 26 is connected, these exhaust passages 47 and 47 are mounted It is connected to a pair of exhaust pipes 49, 49 extending downward along both sides of an oil pan 48 provided on the lower surface of the member 3. Exhaust gas discharged from the exhaust pipes 49, 49 passes through the inside of the extension case 1 and the gear case 15 and is discharged into the water from the boss of the propeller 17.

Water jackets 50a, 50b, 50c, through which cooling water circulates, are formed in the cylinder heads 28, 28 and the cylinder block 26 in which the exhaust ports 40a, 40b,... And the exhaust passages 47, 47 are formed. That is, the water jacket 50a corresponds to the exhaust port 40a of the cylinder head 28, and the water jacket 50b corresponds to the exhaust port 40b of the cylinder block 26.
However, a water jacket 50c is formed corresponding to the exhaust passage 47 of the cylinder block 26, and the cooling water flows into the water jacket 50a from the water jacket 50c via the water jacket 50b.

[0023] The water jacket 50a covering the outside of the exhaust port 40a corresponding to the upper side of the cylinder 34, 34 in each bank 13 _L, 13 _R, the cylinder head 2
Temperature sensors 51, 51 for detecting the wall temperatures of 8, 28 are provided, respectively. The anode metals 52, 5 are provided on the water jackets 50c, 50c of the cylinder block 26, respectively.
2 are provided, and the anode metal 5 is provided.
2, 52 are actively corroded to prevent corrosion of the engine E body.

As described above, the cylinder heads 28, 28
Provided with the temperature sensors 51, 51, the temperature sensors 5 are independent of the size and shape of the cylinder block 26.
Not only can be placed 1 and 51, the outer surface of the cylinder head 28, i.e., left and right banks 13 _L, 1
3 by the temperature sensor 51, 51 provided on the outer surface of the _R, it can be arranged so as not to interfere with the pair of temperature sensors 51, 51 to each other. In addition, by arranging the temperature sensors 51, 51 near the combustion chambers 37, 37, the detection accuracy can be improved.

The temperature sensors 51, 51 detect the temperature of the engine E in an analog manner. The output of the temperature sensors 51, 51 is processed by the controller 32, and when the temperature rises above a predetermined value, the engine overheats. A signal is output. This eliminates the need for a conventionally required overheat switch, thereby reducing the number of components.

[0026] the right bank 13 _R of the cylinder head 28, the oil separation chamber 53 by gas leaked from the combustion chamber 37 ... to the crank chamber is introduced is provided. The blow-by gas from which oil has been separated in the oil separation chamber 53 is passed through the breather passage 54 to the intake silencer 43.
Is led to.

Crank pulley 5 provided at the upper end of crankshaft 12 projecting from the upper surface of cylinder block 26
And a cam pulley 5 provided on a pair of camshafts 56 protruding from the upper surfaces of the pair of cylinder heads 28.
7 _L and 57 _R are connected by an endless belt 59 which is tensioned by a tension pulley 58.

Next, the structure of the fuel supply system of the engine E will be described.

The large-capacity main tank mounted on the hull is connected to a joint 62 at the front of the engine room 11 via a fuel hose (not shown), from which a fuel pipe P ₁ , a filter 63, a fuel pipe P ₂ , Feed pump 64 driven by left camshaft 56 and fuel pipe P ₃
Is connected to the sub-tank 68. The fuel supplied from the main tank to the sub-tank 68 by the feed pump 64 is supplied from the injection pump 78 housed in the sub-tank 68 to the right bank 13 _R via the fuel pipe P ₄ , the filter 83 and the fuel pipe P _5. is supplied to the fuel passage 84 provided, part of the fuel is supplied to the two injectors 46, 46 of the right bank 13 _R. Left bank 13 the remainder of the fuel through the fuel pipe P _6
L is supplied to the fuel passage 85 provided in the left bank 13 _L
Are supplied to the two injectors 46, 46. The excess fuel is returned to the sub-tank 68 through the regulator 88 and the fuel pipe P _7.

Next, the structure of the intake system of the engine E will be described.

The intake system is located in the rear space 3 of the engine room 11.
1 and includes the intake silencer 43, elbow 60, throttle body 44, surge tank 45, and intake ports 38. Intake silencer 43
Is fixed to the head cover 28 of the left bank 13 _L by means such as bolting, and the rear space 31 of the engine room 11 is
Of is disposed on the lower left side, an inlet 43 ₁ intake more air thereafter surface. The elbow 60 connected to the right side surface of the intake silencer 43 is curved upward by 90 ° so as to have a horizontal inlet-side axis and a vertical outlet-side axis, and a throttle body 44 is connected to an upper end thereof. Inside the throttle body 44 and throttle valve 44 ₁ which is opening and closing via a Bowden wire is accommodated, and a downstream portion and an air flow meter 65 of the throttle valve 44 ₁ is connected via a tube 66. The intake silencer 43, the elbow 60, and the throttle body 44 are housed in the rear part of the engine room 11 projecting rearward from the rear end of the extension case 1, whereby the rear space 31 of the engine room 11 is effectively used. .

A lower end of a surge tank 45 having an axis extending in a vertical direction is connected to an upper portion of the throttle body 44, and an intake air temperature sensor 67 is provided at an upper portion thereof. The surge tank 45 includes a pair of left and right flanges 45 ₁ ,
45 ₁ is fixed to the rear surface of the cylinder block 26 by a plurality of bolts 86 ..., the flanges 45 _1, 4
5 to ₁ wherein the fuel passage 84 and 85 each two injectors 46 ... are fixed by bolts 87 ... of the plurality of lines.
The surge tank 45 and the throttle body 44 connected to the lower part thereof are connected to the left and right banks 13 _L and 13 _L of the engine E.
Is accommodated in a space formed between the _R, thereby dead space between both banks 13 _L, 13 _R are effectively used.

The left and right banks 13 _L , 13 _{R of the} engine E
The sub-tank 68 and the intake silencer 43 are arranged outside a space formed therebetween. That is, the engine E
The sub-tank 68 fixed to the throttle body 44 by bolts or the like is disposed on the right side of the center line in the front-rear direction, and the intake silencer 43 is distributed on the left side. The sub tank 68 and the intake silencer 43 can be arranged in the rear space 31 with good balance. In addition, since the large components such as the intake silencer 43 and the sub tank 68 are integrated with the engine E, the engine E can be easily attached to the outboard motor O.

The pair of upper and lower opening 45 ₂ formed on the right side of the surge tank 45, 45 _2, a pair of upper and lower combustion chamber which is formed in the right bank 13 _R of the cylinder head 28 37,3
Is connected to the intake port 38, 38 extending in the 7 and a pair of upper and lower opening 45 ₂ formed on the left side, 45 _2, the left bank 13 a pair of upper and lower combustion chambers 37 and 37 formed in the _L of the cylinder head 28 It is connected to the extended intake ports 38, 38.

As is apparent from FIG. 7, each intake port 3
8 is branched and connected to the upper port 38 ₁ and the lower port 38 ₂ to the two intake ports 69 _1, 69 ₂ of the combustion chambers 37. With respect to a straight line L extending horizontally through the center of a straight line connecting the centers of the pair of intake ports 69 ₁ and 69 ₂ , the upper port 3
8 ₁ and have been displaced by upward the lower port 38 ₂ of the branching point 38 ₃ alpha, nozzles 46 ₁ of the injector 46 is disposed on the straight line L 'extending horizontally through the branching point 38 _3.

[0036] In Thus, air sucked from the air inlet 43 ₁ of the intake silencer 43 to flow into the throttle body 44 via the elbow 60 from the intake silencer 43,
It reaches the surge tank 45 through the throttle valve 44 ₁ which is housed therein. The air in the surge tank 45 is distributed from the four openings 45 ₂ to the four intake ports 38, where the air is mixed with fuel injected from the injectors 46 and provided in the two cylinders 34. Intake is taken into the combustion chamber 37 from the intake valves 39, 39.

[0037] Incidentally, the intake port 38 because of the branches ₁ and upper port 38 and lower port 38 _2, when the flow rate of the mixture of internal suction port 28 to the low speed operation or the like decreases, the fuel component is an intake port 38 bottom wall, that tends to stay in the lower port 38 ₂ of the bottom wall. When the throttle valve 44 ₁ is opened from this state, the intake port 38
Since rise sharply the flow velocity of the mixture passing through the, there is a problem that the accumulated fuel component is at once sucked in over-rich intake port 69 ₂ of the lower side connected to the lower port 38 _2.

[0038] However, as shown in FIG. 7, by which to displace the branch point 38 ₃ of the upper port 38 ₁ and the lower port 38 ₂ by a distance α upwardly, the lower port 38 ₂
The bottom wall is to be tilted strongly downward toward the inlet 69 _{and second} lower. As a result, the fuel component is reduced to the lower port 3
You are not staying in the ₈₂ of the bottom wall, the problem of the throttle valve 44 ₁ is opened can be solved. Moreover, since the nozzles 46 ₁ of the injector 46 is disposed at the same height as the branching portion 38 ₃ of the intake port 38, it is possible to evenly distribute the fuel to ₁ and the upper port 38 and lower port 38 _2.

Although the embodiment of the present invention has been described in detail, the present invention is not limited to the above embodiment, and various design changes can be made.

[0040]

As described above, according to the first aspect of the present invention, an intake passage extending in the cylinder head in a substantially horizontal direction from the combustion chamber and opening to the outer wall of the cylinder head is formed.
The surge tank communicating with the intake passage is arranged on the side of the cylinder head, and the throttle body communicating with the surge tank is arranged below the surge tank. To reduce the amount of protrusion to the side of the engine, thereby making it possible to reduce the size of the engine.

According to a second feature of the present invention, the four-stroke engine is a V-type multi-cylinder four-stroke engine having a pair of banks, and a surge tank is arranged in an area between the pair of banks. Thereby, the dead space between the banks of the V-type multi-cylinder four-cycle engine can be effectively used, and the intake device can be compactly arranged.

According to a third feature of the present invention, the four-stroke engine includes a plurality of cylinders arranged substantially in a vertical direction, and a surge tank is arranged along the plurality of cylinders. The intake device of the cylinder engine can be arranged compactly.

According to the fourth aspect of the present invention, the intake silencer connected to the throttle body is disposed at a position beside the throttle body and not interfering with the cylinder head, thereby including the intake silencer. The intake device can be arranged compactly.

According to a fifth aspect of the present invention, the four-stroke engine is a V-type multi-cylinder four-stroke engine having a pair of banks, wherein a surge tank is disposed in an area between the pair of banks. By arranging the intake silencer outside the region, the intake device including the intake silencer in the V-type multi-cylinder four-cycle engine can be arranged compactly.

According to a sixth aspect of the present invention, the four-stroke engine includes a fuel tank for supplying fuel to the injector, and the fuel tank is disposed on a side of the intake silencer. Can be arranged compactly.

According to a seventh aspect of the present invention, the four-stroke engine has a V-type multi-cylinder 4 having a pair of left and right banks.
In a cycle engine, a surge tank is arranged in a region sandwiched between a pair of left and right banks, and an intake silencer and a fuel tank are arranged side by side outside the region. Both the device and the fuel tank can be arranged compactly.

According to an eighth aspect of the present invention, a four-stroke engine is housed in an engine room defined by an engine cover above an extension case of an outboard motor, with its cylinder generally facing rearward. As a result, the size of the engine room of the outboard motor can be reduced.

According to the ninth feature of the present invention, the engine room protrudes rearward from the rear end of the extension case, and at least a part of the throttle body is housed in the rear protruding portion. The intake device can be arranged by effectively utilizing the dead space of the engine room of the machine.

[Brief description of the drawings]

FIG. 1 is an overall side view of an outboard motor.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is a sectional view taken along line 4-4 in FIG. 3;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 4;

FIG. 6 is a sectional view taken along line 6-6 in FIG. 4;

FIG. 7 is an enlarged view of a main part of FIG. 4 showing an intake port;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Extension case 7 Engine cover 11 Engine room 26 Cylinder block 28 Cylinder head 34 Cylinder 37 Combustion chamber 38 Intake port (intake passage) 43 Intake silencer 44 Throttle body 45 Surge tank 46 Injector 68 Sub tank (fuel tank) E Engine O Outboard motor

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ identification code FI F02M 35/16 F02M 35/10 301P (58) Field surveyed (Int.Cl. ⁷ , DB name) F02B 67/00 F02M 35 / 10 F02M 35/12 F02M 35/16 F02B 75/18

Claims (9)

(57) [Claims] 1. A cylinder block (26) having a substantially horizontal cylinder (34) and a cylinder block (2).
And a combustion chamber (37) formed in the cylinder head (28). The combustion chamber (37) is provided in the cylinder head (28). , A suction tank (45) communicating with the intake passage (38) is formed on the side of the cylinder head (28). And a throttle body (44) communicating with the surge tank (45) is arranged below the surge tank (45).
Intake device for 4-cycle engine. 2. The four-stroke engine (E) is a V-type multi-cylinder four-stroke engine having a pair of banks ( _13L , _13R ), wherein the pair of banks ( _13L , 13R) is provided.
The intake device for a four-stroke engine according to claim 1, wherein the surge tank (45) is arranged in a region sandwiched by _R ). 3. The four-stroke engine (E) includes a plurality of cylinders (34) arranged in a substantially vertical direction, and the surge tank (45) is arranged along a line of the plurality of cylinders (34). 2. The method of claim 1, wherein
An intake device for a four-stroke engine according to claim 1. 4. An intake silencer (43) connected to the throttle body (44) is connected to the throttle body (4).
The intake device for a four-stroke engine according to claim 1, wherein the intake device is disposed at a position which is located on the side of (4) and does not interfere with the cylinder head (28). 5. The four-stroke engine (E) is a V-type multi-cylinder four-stroke engine having a pair of banks ( _13L , _13R ), wherein the pair of banks ( _13L , 13R) is provided.
_R ), the surge tank (45) is arranged in an area sandwiched by the intake silencer (4) outside the area.
The intake device for a four-stroke engine according to claim 4, wherein (3) is arranged. 6. The four-stroke engine (E) includes a fuel tank (68) for supplying fuel to an injector (46), and the fuel tank (68) is disposed on a side of the intake silencer (43). 5. The method according to claim 4, wherein
An intake device for a four-stroke engine according to claim 1. 7. The four-stroke engine (E) is a V-type multi-cylinder four-stroke engine having a pair of left and right banks (13 _L , 13 _R ).
_L , 13 _R ) in the area between the surge tanks (4
7. The intake system for a four-stroke engine according to claim 6, wherein 5) is arranged, and the intake silencer (43) and the fuel tank (68) are arranged side by side outside the region. 8. The four-stroke engine (E) is provided with a cylinder in an engine room (11) defined by an engine cover (7) above an extension case (1) of the outboard motor (O). The intake device for a four-stroke engine according to claim 1, wherein (34) is housed in a substantially backward direction. 9. The engine room (11) projects beyond the rear end of the extension case (1), and the throttle body (4)
The intake device for a four-stroke engine according to claim 8, wherein at least a part of (4) is housed.